Field of the Invention
The invention relates to an admission section of a turbine casing of a steam turbine, in particular an industrial turbine.
In a steam turbine, steam, which serves as a flow medium, is expanded so as to perform work until it condenses. Such a steam turbine or fluid-flow machine having a mechanical output of, for example, 5 to 100 MW is normally used as an industrial turbine. In exactly the same way as a power plant turbine, an industrial turbine is also provided with an admission section, via which live steam fed to the steam turbine flows into the turbine casing. The flow of live steam is adjusted by a number of control valves, which are disposed as individual or group control valves in a valve casing connected to the admission section of the, turbine casing via a flange. Published, Swiss Patent Application CH 665 450 A5, for example, discloses a corresponding flanged joint having an individual throughflow opening. A flanged joint enclosing several throughflow openings is disclosed in International Patent Application WO 85/03986 in which, by use of variable fastening elements, the relative position of the control valve(s) to the turbine casing is adjustable.
At an admission section having a flange-mounted valve casing, in particular in the case of high steam parameters, i.e. at high live-steam pressures and high live-steam temperatures, correspondingly high requirements are imposed on the seal between the admission section of the turbine casing and the control-valve casing.